This invention relates to an air/fuel ratio detector. More particularly, the present invention relates to an air/fuel ratio detector suitable for use in air/fuel ratio control.
Prior art air/fuel ratio detectors include those which detect the ratio on the leaner side of the stoichiometric air/fuel ratio and those which detect the ratio on the richer side of the stoichiometric air/fuel ratio, as disclosed for example in U.S. Pat. Nos. 4,304,652 and 4,300,990. When these detectors are used for the air/fuel ratio control of an internal combustion engine, for example, the detectors must have quick response in order to effect feedback control.
Accordingly, the inventors of this invention produced a wide variety of air/fuel ratio sensors and examined their response characteristics. As a result of studies, the inventors found that if the response speed of the sensors is increased, the sensor output fails to represent a true value and accurate air/fuel ratio control becomes impossible to produce.